207Pb Magnetic Shielding Anisotropy in Pb(NO3)2, PbCO3, PbCrO4, PbMo04 and PbWO4 by Fourier Transform NMR

The NMR signals of 207Pb have been observed in powder samples of Pb (NO3)2, PbCO3 , PbCrO4 , PbMoO4 and PbWO4 using a Fourier transform apparatus. All the observed signals are asymmetrical, indicating anisotropics of the magnetic shielding σ33- σ11 with values between - 56ppm for Pb(NO3)2 and - 884 ppm for PbCrO4 . The principal elements of the shielding ten­ sors σ11 , σ22 , σ33 are given relative to the Pb2+ ion at infinite dilution in H2O and can be referred to the free lead atom with the known shielding constant of earlier measurements.